Ball bat with thinner handle than barrell

ABSTRACT

A tubular metal bat, such as a baseball bat or softball bat, which includes a handle knob to aid in gripping of the bat, a small diameter handle portion, an intermediate tapering portion, a large diameter impact portion, and an end cap. The tubular metal bat having a wall thickness in the handle area that is significantly less than the wall thickness in the impact portion of the bat.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] Not applicable.

BACKGROUND OF THE INVENTION AND PRIOR ART

[0002] 1. Field of Invention

[0003] This invention relates to a tubular metal bat, such as a baseball bat or softball bat, which includes a handle knob to aid in gripping of the bat, a small diameter handle portion, an intermediate tapering portion, a large diameter impact portion, and an end cap. The tubular metal bat having a wall thickness in the handle area that is significantly less than the wall thickness in the impact portion of the bat.

[0004] 2. Description of Prior Art

[0005] Hollow metal bats of aluminum have been developed and have been in use for many years when playing baseball or softball. Improvements and developments have been made in the construction of hollow metal bats since their introduction. Many of the concepts for prior art bats fall into two categories. One category could be summarized as improved single walled bats. These bats have an impact portion of the bat that is made from a tube composed of one material with a generally uniform wall thickness. U.S. Pat. No. 5,626,050 of Ploughe summarizes the standard swaging process used to produce a hollow aluminum bat and further teaches an improved method in which an inner mandrel is used to better control wall thickness throughout the bat. Due to the nature of the swaging process used to manufacture bats, if Phoughe's inner forming mandrel is not used, the wall thickness of the bat increases as the bat diameter decreases. Thus the wall thickness would be a minimum in the impact portion of the bat and maximum in the handle area of the bat. Ploughe teaches a method that allows the reduction of the wall thickness in the trumpet, or transition area, and the handle area with the objective to form metal ball bats with an increased uniformity in wall thickness throughout the bat. Descriptions of other single wall bats and improvements to such bats are described in U.S. Pat. No. 5,393,055 of MacKay, U.S. Pat. No. 5,421,572 of MacKay, U.S. Pat. No. 5,494,280 of MacKay, and U.S. Pat. No. 5,785,614 of MacKay. The improvements in these patents relate to improved designs for end caps or methods of providing a concentrated end weighting, or end loading, to adjust the weight and balance of such a bat.

[0006] The second category of patents could be summarized as multi walled bats. Multi walled bats have a barrel area that utilize two tubes of the same or differing materials. The second wall is designed to improve both the durability and liveliness of the bat. Both walls are generally in contact, but may or may not be bonded to one another. U.S. Pat. No. 1,611,858 of Middlekauff, U.S. Pat. No. 5,364,095 of Easton, U.S. Pat. No. 5,415,398 of Eggiman, U.S. Pat. No. 5,676,610 of Bhatt, U.S. Pat. No. 5,899,823 of Eggiman, U.S. Pat. No. 6,042,493 of Chauvin, and U.S. Pat. No. 6,053,828 of Pitsenberger all disclosure bats that have multiple walls in the barrel area of the bat. Other patents of note that do not fall directly into either the single wall or multi wall categories are U.S. Pat. No. 3,963,239 of Fujii, U.S. Pat. No. 4,241,919 of Foreman, U.S. Pat. No. 5,954,602 of Eggiman and U.S. Pat. No. 6,053,827 of MacKay.

[0007] Few of the prior art patents provide details on the wall thickness in the handle area of the bat relative to the wall thickness in the impact portion of the bat. Destructive examination of several commercially available single wall aluminum softball bats composed of C-405 aluminum from Alcoa of Pittsburgh, Pa. indicates that the average handle thickness is between 0.090 to 0.130 inches thick and that wall thickness in the impact portion of the bat is between 0.065 to 0.080 inches thick. The wall thickness of an aluminum outer shell in bats produced according Eggiman in U.S. Pat. No. 6,042,493 were found to be in the range of about 0.085 to 0.110 inches in the handle area and 0.040 to 0.055 inches in the barrel area.

[0008] Despite the advances claimed in these patents, today's supposedly high performance bats are still susceptible to denting. While the more durable bats are not sufficiently compliant and do not perform well. The number of individual components used in the manufacture the higher performance multi wall bats complicates the manufacturing process, thus increasing the cost to produce them. The use of a high density metal, like a maraging steel alloy, to form the entire bat shell is a radical departure from the significantly lower density aluminum alloys, or titanium alloys, that have exclusively been used in commercial metal bats within the last twenty to thirty years. Neither prior art patents or commercially available bats, nor any combination thereof suggest the unobvious invention of single wall metal bat in which the ratio of the thickness of the wall thickness in the handle of the bat to the wall thickness in the impact portion, or barrel, of the bat is significantly less than one.

SUMMARY OF THE INVENTION

[0009] The object of the present invention is to provide a bat with improved performance and with a minimum number of components. The present invention relates to a tubular bat, which includes a handle knob to aid in gripping of the bat, a small-diameter handle portion, an intermediate tapering portion, a large diameter impact portion, and an end cap. The bat of the invention has a wall thickness in the handle area that is significantly less than the wall thickness in the impact portion of the bat. The bat is ideally formed of a high strength steel alloy.

OBJECTS & ADVANTAGES

[0010] The object and advantages of the present invention are

[0011] (a) to provide a bat with a wall thickness in the handle of the bat that is less than wall thickness in the impact portion of the bat;

[0012] (b) to provide a bat with maximum performance and durability without the added complication of a multi wall construction in the impact portion of the bat;

[0013] (c) to provide a bat shell composed a metal with a density significantly higher than the aluminum alloys commonly used;

[0014] (d) to provide a bat shell with a balance point that is further away from players hands than currently available single wall bat shells;

[0015] (e) to provide a single wall bat in which the need for and the amount of end load material used in each bat is reduced due to the higher balance point of the bat shell;

[0016] (f) to provide a method for producing a bat with a reduced number of components and manufacturing operations;

[0017] (g) to provide a bat with improved performance at a reduced cost.

[0018] The foregoing and additional features and advantages of the present invention will be more readily apparent from a consideration of the ensuing description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a side view of a bat of the present invention.

[0020]FIG. 2 is section view taken along 2-2 of FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0021] Referring to FIG. 1 a bat 10 representative of the newly invented bat. Said bat has a handle knob 18, a small diameter handle area 12 of generally uniform outer diameter, the handle is covered by a synthetic or natural leather grip 20, an intermediate transition zone 14 tapers up to a hitting zone 16 of a generally constant outer diameter, and at the distal end of the bat an end cap 22 is inserted into the hitting zone. The hollow metal tube consisting of the handle area 12, the transition area 14, and the hitting zone 16 will be referred to as the bat shell 30.

[0022]FIG. 2 is section view taken along 2-2 of FIG. 1. This view shows a bat shell 30 having a single wall, an end cap 22, and an end load 24. The end cap 22 can be made from many types of materials including metals, composites, or plastics. The end cap is preferably made using an injection molding process and is composed of a thermoplastic material. Softball bat models are commonly sold in a range of weights to accommodate different players strengths and preferences. Thus a single model of a bat may be sold in 26, 27, 28, 29, 30, 31, and 32 ounce versions. To produce bats in the various weights the same bat shell design will be used in conjunction with different end loads and or end caps.

[0023] To complete the manufacture of this bat, the end cap is inserted into the bat shell and secured using an adhesive and or mechanical locking mechanism. The end load is created using a curable two component liquid urethane and is cast into the shell of the bat by pouring it down through the handle area of the bat that has been positioned vertically with the end cap at the bottom. The end load settles at the bottom of the bat inside the end cap and a portion of the hitting zone, where it hardens into place. Once the urethane hardens the handle knob of the bat is attached to the bat by a welding process. Lastly a grip is wrapped around the handle portion of the bat. These finishing operations are the same as used on commercially available single wall aluminum bats.

[0024] To produce a bat according to the present invention wherein the wall thickness in the barrel area of the bat is significantly thicker than wall thickness in the handle of the bat it is desirable to use a very high strength material to assure maximum strength and durability of the bat. If one tried to make a bat according to the present invention using one of the commonly used aluminum alloys, the bat would either lack liveliness or durability. Using any aluminum alloy, a handle area wall thickness of about 0.090 inches or greater is preferred to prevent failure in the handle area. If one were make a bat according to the current invention using an aluminum alloy with a sufficiently durable handle design, then the wall thickness in the barrel area would need to be significantly greater than 0.090 inches. This would result in a bat with poor performance because the barrel area would be too stiff and limit the trampoline effect of the bat. To maximize the liveliness of an aluminum bat the wall thickness in the impact portion of the bat needs to be less than 0.080 inches and preferably between 0.065 and 0.075 inches. An aluminum bat according to the present invention then would have a handle wall thickness less than 0.080 inches and result in bat that breaks or permanently deforms in the handle of the bat.

[0025] Thus to make a bat that meets the requirements of the present invention requires a material with a significantly higher strength than aluminum and thus allows a thin walled handle to be of sufficient strength. Several such steel alloys meet this requirement, including C-250, C-300, C-350, T-250, T-300 maraging steel available from Allvac located in Monroe, N.C. Other steel alloys that have the desired physically properties include AerMet 100 and AerMet 310 available from Carpenter Specialty Alloys in Wyomissing, Pa. When properly utilized these steel alloys can obtain yield strengths that are greater than 250 ksi.

[0026] Attempts to use swaging equipment and tooling used to swage aluminum alloys into softball bats with steel alloys were unsuccessful. During the swaging process the steel alloys work hardened much quicker than aluminum alloys. As attempts were made to reduce the diameter of the tube, the steel hardened, became brittle and eventually fractured. The swaging trials that were tried attempted to form the entire shell in a single step. It may be possible to swage steel alloys into bats if the swaging process were performed in a series of steps. During each step the tube diameter would be reduced in the appropriate areas of the bat until the work hardening limit is reached. At the point the shell would be removed from the swaging machine and heat-treated to relieve the stresses in the metal. The process would then be repeated as many times as required to form the entire bat into the desired configuration. The process of repeatedly removing the partially formed bat from the swaging machine and heat-treating would likely make this process to expensive to produce a commercially viable bat.

[0027] Two companies that have processes that can produce bat shells to the desired configuration are Dynamic Machine Works Inc. located in Billerica, Mass. and LeFiell located in Sante Fe Springs, Calif. These companies utilize manufacturing processes that reduce the amount of work hardening that occurs when the bat is formed. This allows bat shells to be manufactured in as few as one forming operation. The manufacturing process that would be optimally be used to produce a bat shell according to this invention can in its most general sense be referred to as a spinning operation.

[0028] One other way to produce bat shells using maraging steels would be to form the handle area, the tapered area, and the impact area of the bat in three separate tubes. The three tubes could then be welded together to form the full bat shell. This method may not be suitable for production quantities of bats, but would be suitable for the manufacturing and evaluation of prototype bats in which the wall thickness in a particular section of the bat is varied to determine the effect on performance and durability.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0029] The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom for modifications will become obvious to those skilled in the art upon reading this disclosure and may be made without departing from the spirit of the invention or the scope of the appended claims. One obvious variation would be to increase or decrease the wall thickness of the bat shell in a localized region. This might be done to aid in securing of the handle knob or end cap, or in an attempt to work around the claims of this invention. 

What is claimed:
 1. A bat, comprising: (a) A tubular metal bat shell having a cylindrical handle portion, a cylindrical hitting portion, and a tapered portion coupled to, and extending between the handle and hitting portions. The diameter of the hitting portion being larger than the handle portion. (b) Said bat shell having a wall thickness in the handle area that is significantly less than the wall thickness in the impact portion of the bat.
 2. The bat of claim 1, wherein the ratio of the wall thickness in the handle area of the shell to the wall thickness in the impact portion of the shell is less than 0.95.
 3. The bat of claim 1, wherein the ratio of the wall thickness in the handle area of the shell to the wall thickness in the impact portion of the shell is less than 0.75.
 4. The bat of claim 1, wherein the ratio of the wall thickness in the handle area of the to the wall thickness in the impact portion of the shell is less than 0.6.
 5. The bat of claim 1, wherein the thickness of the handle is less than 0.040 inches.
 6. The bat of claim 1, wherein the thickness of the handle is less than 0.030 inches.
 7. The bat of claim 1, wherein the bat shell is made of a metal with a yield strength greater than 220 ksi.
 8. The bat of claim 1, wherein the bat shell is made of a metal with a yield strength greater than 260 ksi.
 9. A bat comprising: (a) A tubular metal bat shell having a cylindrical handle portion, a cylindrical hitting portion, and a tapered portion coupled to, and extending between the handle and hitting portions. (b) A handle area wall thickness of said bat shell being less than 0.040 inches. (c) The bat shell constructed of a metal with a yield strength greater than 250 ksi.
 10. A bat, comprising: (d) A tubular metal bat shell having a cylindrical handle portion, a cylindrical hitting portion, and a tapered portion coupled to, and extending between the handle and hitting portions. The diameter of the hitting portion being larger than the handle portion. (e) A handle area wall thickness of said bat shell being less than 0.040 inches. (f) The bat shell fabricated such that the ratio of the wall thickness in the handle area of the bat shell to wall thickness in the impact portion of the bat shell is less than 0.075. (g) The bat shell is constructed of a maraging steel alloy with a yield strength greater than 250 ksi. 